SWT Error: Exception in thread “main” java.lang.NoClassDefFoundError: org/eclipse/swt/graphics/Device

Question

I'm making a software using SWT. I have exported it from eclipse to a JAR file using a custom Manifest file:

Manifest-Version: 1.0
Class-Path: swt.jar 
Main-Class: db_hud.HUD_Maker

My Navigation menu looks something like this

Java Project
   - bin
   - src
     + db_hd
       > HUD_Maker.java
       > Classes.java
   - Logfile.txt
   - Manifest.txt
   - swt.jar
   - .classpath
   - .project
org.eclipse.swt
   -All the stuff for SWT (jar, .classpath, etc.)

I have the swt.jar in my classpath with kind lib. I tried changing the Main-Class in the manifest file to include .java in the end, it said "Main Class not found" I do not know how to reproduce this error since I don't know what is the cause of it. If I did I would not be looking for a solution to this problem.

I have tried exporting it as a JAR with the manifest file, but what I get in the console is:

 Exception in thread "main" java.lang.NoClassDefFoundError:

if i just double click i get a JNI Error. No idea what that is...

Can anyone help me? or is this info too little?

Answer 1

Export your java code to a jar file eg hudmaker.jar then put your jar and the swt.jar in a directory. The swt.jar library can be downloaded from eclipse [1]. Open a command line and change to that directory.

Then start your code like this

java.exe -Djava.library.path="." -cp "hudmaker.jar;swt.jar" db_hud.HUD_Maker

As an alternative you can create an executable jar [2].

[1] https://www.eclipse.org/swt/

[2] http://help.eclipse.org/mars/index.jsp?topic=%2Forg.eclipse.jdt.doc.user%2Ftasks%2Ftasks-37.htm